pyrolusite

/pahy-ruh-loo-sahyt, pahy-rol-yuh-sahyt/US // ˌpaɪ rəˈlu saɪt, paɪˈrɒl yəˌsaɪt //UK // (ˌpaɪrəʊˈluːsaɪt) //

辉绿岩,侏罗纪石,辉绿石,侏儒石

Definitions

n.名词 noun

1
- : a common mineral, manganese dioxide, MnO2, the principal ore of manganese, used in various manufactures, as a decolorizer of brown or green tints in glass, and as a depolarizer in dry-cell batteries.

The same pyrolusite (binoxide of manganese) cylinder used with the same thin rod of zinc will precipitate 75 per cent.
Manganese occurs mainly as black oxide (MnO2) in the mineral pyrolusite; and, in a less pure form, in psilomelane and wad.
How does pyrolusite effect the decolorizing of glass containing iron?
As an ore of manganese it is much less abundant than pyrolusite or psilomelane.
Its dioxide (pyrolusite) has been known from very early times, and was at first mistaken for a magnetic oxide of iron.